Intravesicular Phosphatase PHOSPHO1 Function in Enamel Mineralization and Prism Formation.

The transport of mineral ions from the enamel organ-associated blood vessels to the developing enamel crystals involves complex cargo packaging and carriage mechanisms across several cell layers, including the ameloblast layer and the stratum intermedium. Previous studies have established PHOSPHO1 as a matrix vesicle membrane-associated phosphatase that interacts with matrix vesicles molecules phosphoethanolamine and phosphocholine to initiate apatite crystal formation inside of matrix vesicles in bone. In the present study, we sought to determine the function of during amelogenesis.

A Precision Microbiome Approach Using Sucrose for Selective Augmentation of Staphylococcus epidermidis Fermentation against Propionibacterium acnes.

Acne dysbiosis happens when there is a microbial imbalance of the over-growth of s () in the acne microbiome. In our previous study, we demonstrated that (, a probiotic skin bacterium) can exploit glycerol fermentation to produce short-chain fatty acids (SCFAs) which have antimicrobial activities to suppress the growth of . Unlike glycerol, sucrose is chosen here as a selective fermentation initiator (SFI) that can specifically intensify the fermentation activity of , but not .

A Co-Drug of Butyric Acid Derived from Fermentation Metabolites of the Human Skin Microbiome Stimulates Adipogenic Differentiation of Adipose-Derived Stem Cells: Implications in Tissue Augmentation.

We show that Staphylococcus epidermidis, a commensal bacterium in the human skin microbiome, produces short-chain fatty acids by glycerol fermentation that can induce adipogenesis. Although the antimicrobial and anti-inflammatory activities of short-chain fatty acids have been previously well characterized, little is known about the contribution of short-chain fatty acids to the adipogenic differentiation of adipose-derived stem cells (ADSCs). We show that ADSCs differentiated into adipocytes and accumulated lipids in the cytoplasm when cultured with butyric acid, a principal short-chain fatty acid in the fermentation metabolites of S.

Brahma is required for cell cycle arrest and late muscle gene expression during skeletal myogenesis.

Although the two catalytic subunits of the SWI/SNF chromatin-remodeling complex--Brahma (Brm) and Brg1--are almost invariably co-expressed, their mutually exclusive incorporation into distinct SWI/SNF complexes predicts that Brg1- and Brm-based SWI/SNF complexes execute specific functions. Here, we show that Brg1 and Brm have distinct functions at discrete stages of muscle differentiation. While Brg1 is required for the activation of muscle gene transcription at early stages of differentiation, Brm is required for Ccnd1 repression and cell cycle arrest prior to the activation of muscle genes.

Pharmacogenomic and clinical data link non-pharmacokinetic metabolic dysregulation to drug side effect pathogenesis.

Drug side effects cause a significant clinical and economic burden. However, mechanisms of drug action underlying side effect pathogenesis remain largely unknown. Here, we integrate pharmacogenomic and clinical data with a human metabolic network and find that non-pharmacokinetic metabolic pathways dysregulated by drugs are linked to the development of side effects.

Bystander Effect Fuels Human Induced Pluripotent Stem Cell-Derived Neural Stem Cells to Quickly Attenuate Early Stage Neurological Deficits After Stroke.

Unlabelled: : Present therapies for stroke rest with tissue plasminogen activator (tPA), the sole licensed antithrombotic on the market; however, tPA's effectiveness is limited in that the drug not only must be administered less than 3-5 hours after stroke but often exacerbates blood-brain barrier (BBB) leakage and increases hemorrhagic incidence. A potentially promising therapy for stroke is transplantation of human induced pluripotent stem cell-derived neural stem cells (hiPSC-NSCs). To date, the effects of iPSCs on injuries that take place during early stage ischemic stroke have not been well studied.

Cyparissins A and B, jatrophane diterpenes from Euphorbia cyparissias as Pgp inhibitors and cytotoxic agents against ovarian cancer cell lines.

From the whole plant of Euphorbia cyparissias, two new diterpenes based on jatrophane skeleton, named cyparissins A and B (1 and 2) were isolated. Their chemical structures were established through a combination of nuclear magnetic resonance spectroscopy and mass spectrometric methods. The new cyparissins A and B were tested to evaluate their ability to inhibit P-glycoprotein-mediated multidrug resistance and their cytotoxic activity against A2780 human ovarian cancer cells, both WT and ADR.

Notch Activation of Ca(2+) Signaling in the Development of Hypoxic Pulmonary Vasoconstriction and Pulmonary Hypertension.

Hypoxic pulmonary vasoconstriction (HPV) is an important physiological response that optimizes the ventilation/perfusion ratio. Chronic hypoxia causes vascular remodeling, which is central to the pathogenesis of hypoxia-induced pulmonary hypertension (HPH). We have previously shown that Notch3 is up-regulated in HPH and that activation of Notch signaling enhances store-operated Ca(2+) entry (SOCE), an important mechanism that contributes to pulmonary arterial smooth muscle cell (PASMC) proliferation and contraction.

Structure-guided functional characterization of DUF1460 reveals a highly specific NlpC/P60 amidase family.

GlcNAc-1,6-anhydro-MurNAc-tetrapeptide is a major peptidoglycan degradation intermediate and a cytotoxin. It is generated by lytic transglycosylases and further degraded and recycled by various enzymes. We have identified and characterized a highly specific N-acetylmuramoyl-L-alanine amidase (AmiA) from Bacteroides uniformis, a member of the DUF1460 protein family, that hydrolyzes GlcNAc-1,6-anhydro-MurNAc-peptide into disaccharide and stem peptide.

TGFβ responsive tyrosine phosphatase promotes rheumatoid synovial fibroblast invasiveness.

Objective: In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) that line joint synovial membranes aggressively invade the extracellular matrix, destroying cartilage and bone. As signal transduction in FLS is mediated through multiple pathways involving protein tyrosine phosphorylation, we sought to identify protein tyrosine phosphatases (PTPs) regulating the invasiveness of RA FLS. We describe that the transmembrane receptor PTPκ (RPTPκ), encoded by the transforming growth factor (TGF) β-target gene, PTPRK, promotes RA FLS invasiveness.

Generation of myospheres from hESCs by epigenetic reprogramming.

Generation of a homogeneous and abundant population of skeletal muscle cells from human embryonic stem cells (hESCs) is a requirement for cell-based therapies and for a "disease in a dish" model of human neuromuscular diseases. Major hurdles, such as low abundance and heterogeneity of the population of interest, as well as a lack of protocols for the formation of three-dimensional contractile structures, have limited the applications of stem cells for neuromuscular disorders. We have designed a protocol that overcomes these limits by ectopic introduction of defined factors in hESCs--the muscle determination factor MyoD and SWI/SNF chromatin remodeling complex component BAF60C--that are able to reprogram hESCs into skeletal muscle cells.

Propionic acid and its esterified derivative suppress the growth of methicillin-resistant Staphylococcus aureus USA300.

Previously, we demonstrated that Propionibacterium acnes, a human skin commensal bacterium, ferments glycerol into short-chain fatty acids, including propionic acid. Propionic acid suppressed the growth of Staphylococcus aureus USA300, a community-acquired methicillin-resistant bacterium, in vitro and in vivo. In this study, it is demonstrated that the anti-USA300 activity of propionic acid persisted after buffering the acid with 4-(2-hydroxyethyl)-1- piperazineethanesulfonic acid.

Downstream signaling and genome-wide regulatory effects of PTK7 pseudokinase and its proteolytic fragments in cancer cells.

Background: The full-length membrane protein tyrosine kinase 7 (PTK7) pseudokinase, an important component of the planar cell polarity and the Wnt canonical and non-canonical pathways, is a subject of step-wise proteolysis in cells and tissues. The proteolysis of PTK7 involves membrane type-matrix metalloproteinase (MT1-MMP), members of the Disintegrin Domain and Metalloproteinase (ADAM) family, and γ-secretase. This multi-step proteolysis results in the generation of the digest fragments of PTK7.

Drosophila as a potential model to ameliorate mutant Huntington-mediated cardiac amyloidosis.

Several human diseases, including Huntington's disease (HD), are associated with the expression of mutated, misfolded, and aggregation-prone amyloid proteins. Cardiac disease is the second leading cause of death in HD, which has been mainly studied as a neurodegenerative disease that is caused by expanded polyglutamine repeats in the huntingtin protein. Since the mechanistic basis of mutant HD-induced cardiomyopathy is unknown, we established a Drosophila heart model that exhibited amyloid aggregate-induced oxidative stress, resulting in myofibrillar disorganization and physiological defects upon expression of HD-causing PolyQ expression in cardiomyocytes.

Huntington's disease induced cardiac amyloidosis is reversed by modulating protein folding and oxidative stress pathways in the Drosophila heart.

Amyloid-like inclusions have been associated with Huntington's disease (HD), which is caused by expanded polyglutamine repeats in the Huntingtin protein. HD patients exhibit a high incidence of cardiovascular events, presumably as a result of accumulation of toxic amyloid-like inclusions. We have generated a Drosophila model of cardiac amyloidosis that exhibits accumulation of PolyQ aggregates and oxidative stress in myocardial cells, upon heart-specific expression of Huntingtin protein fragments (Htt-PolyQ) with disease-causing poly-glutamine repeats (PolyQ-46, PolyQ-72, and PolyQ-102).

Altered rate-dependent depression of the spinal H-reflex as an indicator of spinal disinhibition in models of neuropathic pain.

The unpredictable efficacy of current therapies for neuropathic pain may reflect diverse etiological mechanisms operating between, and within, diseases. As descriptions of pain rarely establish specific mechanisms, a tool that can identify underlying causes of neuropathic pain would be useful in developing patient-specific treatments. Rate-dependent depression (RDD), a measure of the change in amplitude of the Hoffman reflex over consecutive stimulations, is attenuated in diabetic rats that also exhibit impaired spinal γ-aminobutyric acid (GABA)A receptor function, reduced spinal potassium chloride co-transporter (KCC2) expression, and indices of painful neuropathy.

DNA damage-activated ABL-MyoD signaling contributes to DNA repair in skeletal myoblasts.

Previous works have established a unique function of MyoD in the control of muscle gene expression during DNA damage response in myoblasts. Phosphorylation by DNA damage-activated ABL tyrosine kinase transiently inhibits MyoD-dependent activation of transcription in response to genotoxic stress. We show here that ABL-MyoD signaling is also an essential component of the DNA repair machinery in myoblasts exposed to genotoxic stress.

Structure of the inositol-1-phosphate cytidylyltransferase from Thermotoga maritima.

The unique steps in the synthesis of an unusual osmolyte in hyperthermophiles, di-myo-inositol-1,1'-phosphate (DIP), involve the production of CDP-inositol and its condensation with an inositol-1-phosphate molecule to form phosphorylated DIP. While many organisms fuse both activities into a single enzyme, the two are separate in Thermotoga maritima. The crystal structure of the T.

Epigenetic reprogramming of human embryonic stem cells into skeletal muscle cells and generation of contractile myospheres.

Direct generation of a homogeneous population of skeletal myoblasts from human embryonic stem cells (hESCs) and formation of three-dimensional contractile structures for disease modeling in vitro are current challenges in regenerative medicine. Previous studies reported on the generation of myoblasts from ESC-derived embryoid bodies (EB), but not from undifferentiated ESCs, indicating the requirement for mesodermal transition to promote skeletal myogenesis. Here, we show that selective absence of the SWI/SNF component BAF60C (encoded by SMARCD3) confers on hESCs resistance to MyoD-mediated activation of skeletal myogenesis.

Loss of OPA1 disturbs cellular calcium homeostasis and sensitizes for excitotoxicity.

Optic atrophy 1 (OPA1) mutations cause dominant optic atrophy (DOA) with retinal ganglion cell (RGC) and optic nerve degeneration. The mechanism for the selective degeneration of RGCs in DOA remains elusive. To address the mechanism, we reduced OPA1 protein expression in cell lines and RGCs by RNA interference.

Insights into ectodomain shedding and processing of protein-tyrosine pseudokinase 7 (PTK7).

The membrane PTK7 pseudokinase, a component of both the canonical and noncanonical/planar cell polarity Wnt pathways, modulates cell polarity and motility in biological processes as diverse as embryo development and cancer cell invasion. To determine the individual proteolytic events and biological significance of the ectodomain shedding in the PTK7 function, we used highly invasive fibrosarcoma HT1080 cells as a model system. Current evidence suggested a likely link between PTK7 shedding and cell invasion in our HT1080 cell model system.

Stem cell heterogeneity: implications for aging and regenerative medicine.

For decades, hematopoietic stem cells (HSCs) were thought to be a homogeneous population of cells with flexible behavior. Now a new picture has emerged: The HSC compartment consists of several subpopulations of HSCs each with distinct, preprogrammed differentiation and proliferation behaviors. These programs are epigenetically fixed and are stably bequeathed to all daughter HSCs on self-renewal.

Signal-dependent incorporation of MyoD-BAF60c into Brg1-based SWI/SNF chromatin-remodelling complex.

Tissue-specific transcriptional activators initiate differentiation towards specialized cell types by inducing chromatin modifications permissive for transcription at target loci, through the recruitment of SWItch/Sucrose NonFermentable (SWI/SNF) chromatin-remodelling complex. However, the molecular mechanism that regulates SWI/SNF nuclear distribution in response to differentiation signals is unknown. We show that the muscle determination factor MyoD and the SWI/SNF subunit BAF60c interact on the regulatory elements of MyoD-target genes in myoblasts, prior to activation of transcription.

Id3 upregulates BrdU incorporation associated with a DNA damage response, not replication, in human pancreatic β-cells.

Elucidating mechanisms of cell cycle control in normally quiescent human pancreatic β-cells has the potential to impact regeneration strategies for diabetes. Previously we demonstrated that Id3, a repressor of basic Helix-Loop-Helix (bHLH) proteins, was sufficient to induce cell cycle entry in pancreatic duct cells, which are closely related to β-cells developmentally. We hypothesized that Id3 might similarly induce cell cycle entry in primary human β-cells.

Early acquisition of neural crest competence during hESCs neuralization.

Background: Neural crest stem cells (NCSCs) are a transient multipotent embryonic cell population that represents a defining characteristic of vertebrates. The neural crest (NC) gives rise to many derivatives including the neurons and glia of the sensory and autonomic ganglia of the peripheral nervous system, enteric neurons and glia, melanocytes, and the cartilaginous, bony and connective tissue of the craniofacial skeleton, cephalic neuroendocrine organs, and some heart vessels.

Methodology/principal Findings: We present evidence that neural crest (NC) competence can be acquired very early when human embryonic stem cells (hESCs) are selectively neuralized towards dorsal neuroepithelium in the absence of feeder cells in fully defined conditions.